Geoffrey Lean is Britain's longest-serving environmental correspondent, having pioneered reporting on the subject almost 40 years ago.

Ministers get another fright over planning, but seem incapable of learning lessons

If ministers had the slightest doubt that their ill-conceived planning reforms were politically explosive, it will have finally been dispelled when the Government narrowly escaped defeat in the House of Commons this week.

Sixteen Conservatives and eight Liberal Democrats defied a three-line whip on Tuesday, rebelling against plans to force councils to allow homeowners to build extensions up to 26ft long – double the present limit – without having to get planning permission, and ministers only scraped through at all by promising to think again.

When the measure – strongly backed by George Osborne – was first mooted, it must have seemed straightforward enough, particularly compared with last year's long battle over the National Policy Planning Framework, when ministers had to modify their original “builders' charter” markedly as a result of campaigns by The Daily Telegraph, the National Trust and the Campaign to Protect Rural England. What could be less controversial, after all, than allowing Englishmen to extend their castles, without having to kowtow to town-hall bureaucrats – especially when an increase in building could help embattled small builders?

But – as so often – the jolly wheeze had not been thought through. Every expansionist householder, after all, has a couple of neighbours who don't want their views spoiled – and possibly the value of their properties diminished – by an unsightly big edifice next door. Oddly the Government used to understand this – one of its first acts was to discourage houses being built in back gardens – but such sensibilities seem to have faded as fast as their commitment to giving local people, and councils, more control over planning decisions.

To add insult to injury, it also became clear that the policy was designed to address a largely non-existent problem. Ninety per cent of extensions already get planning permission, so only relatively few more would be built – mainly the ugliest and most objectionable ones – and builders would benefit little.

Predictably, councils across the country revolted. “We have seldom had a situation where so many Conservative councillors and councils and other bodies have united to say this is very bad legislation,” Tory MP Stewart Jackson told the Commons. And his colleague Zac Goldsmith, who led the revolt, called it “very bad, clumsy politics”.

That could go for much of the planning policies of ministers, who – failing to learn from last year's debacle – often act as if their original proposed NPPF had come into force, instead of being watered down, thus stoking up trouble all over their heartlands. Will they now learn a lesson from their further humiliation this week? Don't bet your house – or even your extension – on it.